Monday, March 18, 2013

Life Expectancy for U.S. Women Heading Down?

In a previous post I predicted that U.S. life expectancies will peak soon and begin to go down by 2020. This process has already begun, for U.S. women. A report this month in Health Affairs offered this chilling announcement:

We examined trends in male and female mortality rates from 1992–96 to 2002–06 in 3,140 US counties. We found that female mortality rates increased in 42.8 percent of counties, while male mortality rates increased in only 3.4 percent.

This is not the first study of its kind to report such a result. The New York Times devoted a story to the decline in female life expectancies last September (wherein it quoted from an August 2012 Health Affairs piece), and in June 2011 a far more extensive report appeared in Population Health Metrics, with similar findings. Even before that, a 2008 PLoS report by researchers from Harvard, U.C. San Francisco, and the University of Washington found life expectancy for U.S. women "began to level off or even decline in the 1980s for 4 percent of men and 19 percent of women." Bottom line, this is a process that started many years ago, and it has been verified repeatedly by different teams of researchers.

Counties in which female life expectancy is heading down are shown in red.

Some of the decline in life expectancy has been linked to educational level. In 1990, the difference in life expectancy between the most educated white females and the least educated was about 2 years. Now it's 10.4 years. No one has explained why lack of education should be deadlier today than in 1990. It's true that less-educated women smoke more tobacco than better-educated women, but that was true in 1990 as well. And anyway, in order to explain a life-expectancy delta of 10.4 years, one hundred percent of less-educated women would have to smoke, and one hundred percent of educated women would have to be lifetime non-smokers. Which is pretty far from the case.

Some experts have tried to pin the blame on rising obesity, but this is likely a red herring as well. For example, obesity rates for women barely changed from 1999 to 2010. It's interesting to note, too, that obesity is more prevalent among Hispanic women than non-Hispanic white women (by a solid margin) and yet life expectancy for Hispanic U.S. females is 83.7 years (CDC data), far higher than the national average (for U.S. women) of 81.1 years.

What's changed for women in the last 30 years? In a macro sense, the biggest change is that they've entered the workforce in huge numbers. Female participation in the labor force went from under 40% in 1960 to just over 60% in 1997 (where it's stayed ever since). It stands to reason that if you acquire the lifestyle habits of men (such as working outside the home every day), you'll perhaps be exposed to the same stressors that men are exposed to and acquire some of the same mortality risks. Especially if you're working harder, for less money.

There are no doubt other factors to consider. The greater question is whether the number of counties in which female life expectancy is on the decline will continue to grow until it includes nearly every county in the U.S., or whether the current trend represents a demographic split of some kind (between the well-educated and the low-educated, or between high earners and low earners). It also remains to be seen whether male life expectancies will also soon start to go down across the country. I suspect we'll see some interesting demographic trends soon, showing white Americans to be doing particularly poorly compared to non-whites. (Blacks and Hispanics are still making strong life-expectancy gains.) Time will tell.